Commitment and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2013
Loss Contingencies [Line Items]
Rent expense	$ 11.5	$ 10.5	$ 10.4
Incentive awarded to the company by the State of Connecticut, total	11.5
Incentive awarded to the company by the State of Connecticut, non-interest bearing loans	8.0
Incentive awarded to the company by the State of Connecticut, grants	3.5
Non-interest bearing incentive loan term	10 years
Incentive awarded to the company by the State of Connecticut, revenue recognized	0.3
Incentive awarded to the company by the State of Connecticut, deferred revenue	$ 7.2			$ 7.5
Maximum
Loss Contingencies [Line Items]
Noncancellable operating leases expiration year	2023